WO2007039975A1

WO2007039975A1 - Illuminating device and display using same

Info

Publication number: WO2007039975A1
Application number: PCT/JP2006/314274
Authority: WO
Inventors: Yuuki Ohta; Tetsuya Hamada; Noriyuki Ohhashi
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2005-09-30
Filing date: 2006-07-19
Publication date: 2007-04-12
Also published as: CN101278151A; CN100587322C; JP4627319B2; US7911559B2; JPWO2007039975A1; US20090231513A1

Abstract

Disclosed is an illuminating device emitting surface light wherein high luminance is realized by improving the utilization efficiency of light from the light source. Specifically disclosed is a backlight device (10) comprising a light guiding body (11), LED units (20) arranged opposite to side faces (11a, 11b) of the light guiding body (11). By having the light from the LED units incident on the side faces propagate in the light guiding body (11), surface light is emitted from a major surface (11d) of the light guiding body (11). The backlight device (10) also comprises an insulating reflection sheet (12) arranged outside the other major surface of the light guiding body (11) opposite to the major surface (11d), and a metal reflection sheet (13) arranged on the opposite side of the light guiding body (11) with respect to the insulating reflection sheet (12).

Description

Specification

LIGHTING DEVICE AND DISPLAY DEVICE USING THE SAME

Technical field

The present invention relates to a so-called surface-emitting illumination device that emits planar light, and more particularly, to an illumination device used as a backlight of a liquid crystal display device.

Background art

In recent years, liquid crystal display devices having features such as low power consumption, thinness, and light weight have been widely used as display devices for television receivers, personal computers, mobile phones, and the like. The liquid crystal display element is a so-called non-light emitting display element that does not emit light. Therefore, for example, a configuration in which a surface-emitting illumination device (so-called backlight) is provided on one main surface of the liquid crystal display element or a configuration in which ambient light is incident on the liquid crystal display element as illumination light is employed. The former configuration is referred to as a transmissive liquid crystal display device, and the latter configuration is referred to as a reflective liquid crystal display device. In addition, a so-called transflective liquid crystal display device that uses ambient light as illumination light and, if necessary, illumination light from a backlight is also known.

[0003] Backlights are roughly classified into direct type and sidelight (also referred to as edge light) types according to the arrangement of light sources with respect to the liquid crystal display element. A direct-type backlight has a light source arranged on the back side of the liquid crystal display element, and a diffuser plate, a prism sheet, etc. are arranged between the light source and the liquid crystal display element so that the entire back surface of the liquid crystal display element is uniform It is configured to allow planar light to enter.

[0004] On the other hand, the sidelight-type backlight is disposed so as to face the light guide disposed on the back side of the liquid crystal display element and the side surface of the light guide (side portion of the liquid crystal display element). It has a light source. The light from the light source is introduced into the light guide from the side surface of the light guide. The light introduced into the inside of the light guide propagates while being totally reflected inside the light guide, and is emitted toward the back of the liquid crystal display element!

[0005] Conventionally, in a sidelight type backlight, in order to improve the luminance by re-entering light that leaks to the side opposite to the liquid crystal display element, it faces the light exit surface to the liquid crystal display element. A configuration in which a reflective sheet is disposed outside the surface is known (for example, Japanese Patent Laid-Open No. 2002-2002) — See 75038 (FIG. 1), JP 2003-156739 (FIG. 2, paragraph 0024), JP 2003-279972 (FIG. 2), and the like. As such a reflection sheet, an aluminum foil sheet, a film sheet in which a white pigment is dispersed, or a film sheet formed with an aluminum metal film or the like is used! (Japanese Patent Laid-Open No. 2002-75038, See paragraph 0031).

[0006] By the way, recently, development of light emitting diodes (LEDs) has progressed, and LEDs have been suitably used as a light source for backlights. FIG. 7 is a plan view showing an example of an LED unit conventionally used as a knock light source. The LED unit 20 shown in FIG. 7 has a configuration in which a plurality of LEDs 22 are arranged in a row on one main surface of the substrate 21. As the LED 22, a white LED or an LED that emits light of each color of RGB is used. Each of the LEDs 22 has a wiring terminal 23. This terminal 23 is exposed on the surface of the substrate 21.

FIG. 8 is a cross-sectional view showing an example of a conventional backlight device 90 using the LED unit 20 as a light source. A conventional knocklight device 90 shown in FIG. 8 includes a light guide 91. The LED units 20 are arranged on both side surfaces of the light guide 91 so that light emitted from the LEDs 22 enters the side surfaces of the light guide 91. An optical sheet such as a diffusion sheet 92 or a prism sheet (not shown) is laminated on the light emitting surface of the light guide 91 as necessary. A reflection sheet 93 is disposed outside the light guide 91 on the side opposite to the light exit surface.

In the conventional backlight device 90 shown in FIG. 8, since the terminal 23 of the LED unit 20 is exposed on the surface of the substrate 21 on the side surface of the light guide 91 as described above, a short circuit of the LED 22, etc. In order to prevent this, the reflection sheet 93 needs to be formed of an insulating material. That is, when a metal stay or a metal vapor deposition sheet is used as the reflection sheet 93, the LED 22 may be short-circuited when the end of the reflection sheet 93 contacts the terminal 23. As the reflective sheet 93 made of an insulating material, an insulating film sheet in which a white pigment is dispersed, an insulating film sheet to which a white paint is applied, or the like is used.

[0009] However, these insulating film sheets generally have good light scattering properties but low light reflectivity compared to metal foil and metal vapor-deposited sheets.

Disclosure of the invention In view of this problem, an object of the present invention is to provide an illuminating device with higher brightness by improving utilization efficiency of light from a light source in an illuminating device that emits planar light. . Another object is to provide a high-quality liquid crystal display device using the lighting device.

[0011] In order to achieve the above object, an illumination device according to the present invention includes a light guide and a light emitting element disposed to face a side surface of the light guide, from the light emitting element to the side surface. In an illuminating device that emits planar light from one main surface of the light guide by propagating the incident light inside the light guide, a main surface facing the one main surface of the light guide An insulating reflecting member installed outside and a metal reflecting member laminated on the opposite side of the light guide in the insulating reflecting member.

[0012] A liquid crystal display device according to the present invention includes the above-described illumination device according to the present invention and a liquid crystal display element.

[0013] According to the present invention, in an illuminating device that emits planar light, a higher-luminance illuminating device can be realized by improving the utilization efficiency of light from a light source. In addition, a high-quality liquid crystal display device using the lighting device can be realized.

Brief Description of Drawings

FIG. 1 is an exploded perspective view showing a schematic configuration of a backlight device according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view showing a state where the backlight device shown in FIG. 1 is cut along the XZ plane shown in FIG.

FIG. 3 is a cross-sectional view showing a configuration of a backlight device as a modification of the illumination device according to the first embodiment.

FIG. 4 is a cross-sectional view of a backlight device according to Embodiment 2 of the present invention.

FIG. 5 is a cross-sectional view of a backlight device according to Embodiment 3 of the present invention.

FIG. 6 is a cross-sectional view of a liquid crystal display device according to Embodiment 4 of the present invention.

FIG. 7 is a plan view showing an example of an LED unit conventionally used as a knocklight light source.

FIG. 8 shows an example of a conventional backlight device using an LED unit as a light source. It is sectional drawing.

BEST MODE FOR CARRYING OUT THE INVENTION

[0015] An illuminating device according to the present invention includes a light guide and a light emitting element disposed to face a side surface of the light guide, and guides light incident on the side surface from the light emitting element. In an illuminating device that emits planar light from one main surface of the light guide by being propagated inside the body, an insulating property installed outside the main surface facing the one main surface of the light guide A reflection member, and a metal reflection member laminated on the opposite side to the light guide in the insulating reflection member.

[0016] According to this configuration, since the metal reflecting member is laminated on the side opposite to the light guide in the insulating reflecting member, a slight leak light transmitted through the insulating reflecting member can Reflected by the reflecting member and re-enters the light guide. As a result, the utilization efficiency of light from the light source is improved, and a lighting device with higher brightness can be realized.

[0017] In the illumination device, the light emitting element has a wiring terminal at a position facing a side surface of the light guide, and the metal reflecting member has conductivity, and the light guide It is preferable that a length of the metal reflecting member in a normal direction of a side surface facing the light emitting element is shorter than a length of the insulating reflecting member. According to this configuration, the length of the metal reflecting member in the normal direction of the side surface facing the light emitting element in the light guide is shorter than the length of the insulating reflecting member. This is because the metal reflective member can be prevented from coming into contact with the wiring terminals of the light emitting element.

[0018] In addition, in the preferable configuration described above, it is preferable that an insulating member is further provided between an end portion of the metal reflecting member and the wiring terminal. It is because it can prevent more reliably that a conductive metal reflective member contacts the wiring terminal of a light emitting element.

[0019] In the above illumination device, the light emitting element has a wiring terminal at a position facing the side surface of the light guide, the metal reflecting member has conductivity, and an end of the metal reflecting member It is preferable that an end portion of the insulating reflecting member is interposed between the wiring portion and the wiring terminal. According to this configuration, since the end portion of the insulating reflecting member is interposed, it is possible to more reliably prevent the conductive metal reflecting member from contacting the wiring terminal of the light emitting element. [0020] Further, in the above illumination device, the insulating reflection is provided between an end portion of the insulating reflecting member and the metal reflecting member in a normal direction of a side surface facing the light emitting element in the light guide. It is preferable that a pressing member that presses the end of the member toward the light emitting element is provided. In this configuration, by pressing the end of the insulating reflecting member toward the light emitting element with the pressing member, it is possible to eliminate a gap that generates light leakage between the insulating reflecting member and the lower portion of the light emitting element. As a result, the light utilization efficiency is further improved, and a backlight device with higher luminance can be realized.

[0021] Further, a liquid crystal display device according to the present invention includes the illumination device according to any one of the above-described configurations and a liquid crystal display element. According to this configuration, a liquid crystal display device with high display quality can be realized by providing a high-luminance illumination device.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

[0023] (Embodiment 1)

FIG. 1 is an exploded perspective view showing a schematic configuration of a backlight device 10 as an illuminating device according to an embodiment of the present invention. As shown in FIG. 1, the knocklight device 10 includes a light guide 11, an insulating reflection sheet 12, a metal reflection sheet 13, a frame 14, and an LED unit 20. In FIG. 1, the force LED unit 20 shown with only one LED unit 20 is provided on both side surfaces of the light guide 11 (see FIG. 2). The configuration of the LED unit 20 is as shown in FIG. 7. As the LED 22 (light emitting element), a white LED or an LED that emits each color light of RGB is used.

FIG. 2 is a cross-sectional view of the backlight device 10 along a plane (XZ plane shown in FIG. 1) orthogonal to both the main surface of the substrate 21 of the LED unit 20 and the main surface of the light guide 11. It is. As shown in FIGS. 1 and 2, the knock light device 10 includes a metal reflection sheet 13, an insulating reflection sheet 12, and a light guide 11 laminated in this order on a main surface 14c of a frame 14. It is the composition which becomes. Note that a diffusion sheet, a prism sheet, or the like may be provided above the light exit surface l id of the force light guide 11 (not shown in FIGS. 1 and 2). Further, the LED unit 20 is installed so as to face each of the pair of side faces 11a and ib facing each other in the light guide 11.

[0025] In FIGS. 1 and 2, the dimensions of each part are different from the actual configuration in order to easily explain the characteristics of the present invention. For example, the vertical / horizontal dimension ratio of the light guide 11 in FIG. Is different from the actual one. Further, the thicknesses of the metal reflection sheet 13 and the insulating reflection sheet 12, the interval between these sheets, and the like are exaggerated for easy understanding of the present invention. Actually, the light guide 11, the metal reflection sheet 13, and the insulating reflection sheet 12 are laminated with almost no gap.

In the backlight device 10, the LED unit 20 is attached along the side wall 14 b of the frame 14. That is, as shown in FIG. 2, the substrate 21 of the LED unit 20 is fixed to the side wall 14b of the frame body 14 by an adhesive, screws, or the like (both not shown). The light guide 11 is disposed such that its side surface faces the LED 22 of the LED unit 20. As a result, light emitted from the LED 22 is introduced from the side surface of the light guide 11 into the light guide.

[0027] The light guide 11 is a flat plate made of a transparent resin such as acrylic resin. The insulating reflective sheet 12 is polyethylene terephthalate (PET) colored white by dispersing a white pigment or applying a white paint. The metal reflection sheet 13 is a PET sheet on which silver is deposited. The frame 14 is made of metal or grease.

[0028] However, the materials of the insulating reflective sheet 12 and the metal reflective sheet 13 are not limited to the above examples. Materials for the insulating reflective sheet 12 include polyester-based resin (including the above PET), polycarbonates (for example, bisphenol A-based polycarbonate), polyolefins (for example, polyethylene, polypropylene, etc.), and cellulose dielectrics ( For example, cell mouth one triacetate), bull resin (polysalt vinylidene), polyimides, polyamides, polyethersulfone, polysulfone resin, polyarylate resin, fluorine resin, etc. it can. Further, as the metal reflection sheet 13, the silver foil, the aluminum foil, the foil of the alloy mainly composed of silver, the foil of the alloy mainly composed of aluminum, or the silver deposited sheet, the aluminum deposited sheet, the alloy mainly composed of silver. It is possible to use a sheet vapor-deposited or a sheet vapor-deposited an alloy mainly composed of aluminum.

As described above, by arranging the metal reflection sheet 13 below the insulating reflection sheet 12, even a small amount of light transmitted through the insulation reflection sheet 12 is reflected by the metal reflection sheet 13 and guided to the light guide 11. Re-enters. The metal reflective sheet 13 using aluminum, silver, or an alloy thereof has a higher reflectance than the insulating reflective sheet 12 colored in white. Power. As a result, the light use efficiency is improved, and the brightness of the knocklight device 10 can be improved.

As shown in FIG. 2, the width W of the insulating reflective sheet 12 is larger than the width W of the light guide 11.

12 11

. Thus, the width W of the insulating reflective sheet 12 should be larger than the width W of the light guide 11.

12 11

As a result, light can be prevented from leaking from the gap between the light guide 11 and the LED 22 to the opposite side of the light exit surface 1 Id.

[0031] Further, the width W of the insulating reflective sheet 12 is such that the LED 22 in the two LED units 20

12

It is preferably greater than the distance W between the surfaces. Thus, the width of the insulating reflective sheet 12

twenty two

W is larger than the distance W between the surfaces of the LEDs 22 in the two LED units 20

12 22

As a result, it is possible to more reliably prevent light from leaking from the gap between the light guide 11 and the LED 22 to the side opposite to the light exit surface id. In the configuration illustrated in FIG. 2, there is a slight gap between the insulating reflective sheet 12 and the terminal 23 of the LED unit 20. Even if the end of the insulating reflective sheet 12 contacts the terminal 23, there is no problem. There is no.

[0032] The width W of the metal reflecting sheet 13 is smaller than the width W of the insulating reflecting sheet 12.

13 12

Has been. The width W of the metal reflection sheet 13 is the same as the LED22 in the two LED units 20.

13

It is preferable that the distance W is larger than the distance W between the surfaces of

twenty two

It is necessary to make it the range that does not touch the terminal 23 of the unit 20.

In addition, as shown in FIG. 1, a cut-and-raised portion 14a is provided in a part of the side of the frame 14 where the LED unit 20 is not attached. Further, a cutout 13a is formed at a position overlapping the cut and raised portion 14a in the metal reflection sheet 13. Further, also in the insulating reflective sheet 12, a notch 12a is formed at a position overlapping the cut and raised portion 14a. Therefore, the cut-and-raised portion 14a is fitted to the notch 13a of the metal reflecting sheet 13 and the notch 12a of the insulating reflecting sheet 12, so that the metal reflecting sheet 13 and the insulating reflecting sheet 12 are in the X direction. Is prevented from being displaced. The light guide 11 is formed so that the side surface 11c is cut and raised when it is assembled in the frame 14.

[0034] Means for preventing displacement of the metal reflecting sheet 13 and the insulating reflecting sheet 12 is not limited to the fitting between the cut-and-raised part and the notch as described above. For example, a positioning pin is provided at at least one place on the frame 14 and the metal is matched to the pin position. A hole may be provided in the reflection sheet 13 and the insulating reflection sheet 12.

As described above, the knocklight device 10 according to the present embodiment has the effect that the luminance is improved by providing the metal reflection sheet 13 under the insulating reflection sheet 12. In addition, the width W of the metal reflecting sheet 13 is smaller than the width W of the insulating reflecting sheet 12.

13 12

This prevents the end portion of the metal reflection sheet 13 from coming into contact with the terminal 23 of the LED unit 20.

FIG. 3 is a cross-sectional view showing a configuration of a backlight device 30 as a modified example of the lighting device that works on the present embodiment. As shown in FIG. 3, the backlight device 30 is similar to the backlight device 10 in that the light guide 11, the insulating reflective sheet 12, the metal reflective sheet 13, the frame 14, the LED unit 20, It has. However, the knock light device 30 is a knock light in that an insulating member 31 is provided between both ends of the metal reflection sheet 13 (both ends in the X direction shown in FIG. 3) and the terminal 23 of the LED unit 20. Different from device 10.

[0037] The insulating member 31 can be formed using, for example, PET (polyester), silicon, rubber tape, or the like as a material. Further, the insulating member 31 is fixed to the frame body 14, fixed to the terminal 23 of the LED unit 20, or an insulating tape or the like is attached to both ends of the metal reflecting sheet 13, so that the metal reflecting sheet 13 It can be installed between both ends of the and terminals 23.

[0038] The knock light device 30 includes the insulating member between both ends of the metal reflection sheet 13 and the terminal 23, so that the short circuit of the LED 22 by the metal reflection sheet 13 can be prevented more reliably.

[0039] (Embodiment 2)

Another embodiment of the lighting device according to the present invention will be described below. Note that components similar to those described in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted. FIG. 4 is a cross-sectional view of a backlight device 40 as an illumination device that works on the present embodiment.

As shown in FIG. 4, the knock light device 40 is similar to the backlight device 10 according to the first embodiment, in which the light guide 11, the insulating reflective sheet 12, the metal reflective sheet 13, and the frame are provided. 14 and the LED unit 20 are provided. However, the knocklight device 40 is attached to the insulating reflective sheet 12. Both ends (both ends in the X direction in Fig. 4) are bent at a substantially right angle below the LED 22, and are interposed between the end of the metal reflecting sheet 13 and the terminal 23 of the LED unit 20. This is different from the backlight device 10 in the form 1.

That is, the knocklight device 40 is described in Embodiment 1 because the insulating reflective sheet 12 is interposed between the end of the metal reflective sheet 13 and the terminal 23 of the LED unit 20. In addition to the effect of the backlight device 10, the short circuit of the LED 22 due to the metal reflection sheet 13 can be prevented more reliably.

[Embodiment 3]

Another embodiment of the lighting device according to the present invention will be described below. Note that components similar to those described in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted. FIG. 5 is a cross-sectional view of a backlight device 50 as an illumination device that works on the present embodiment.

As shown in FIG. 5, the knock light device 50 is similar to the backlight device 10 according to the first embodiment. The light guide 11, the insulating reflective sheet 12, the metal reflective sheet 13, and the frame 14 and the LED unit 20 are provided. However, the knocklight device 50 is substantially wedge-shaped between the insulating reflective sheet 12 and the metal reflective sheet 13 along the sides of both ends of the insulating reflective sheet 12 (both ends in the X direction in FIG. 5). This is different from the backlight device 10 of Embodiment 1 in that a spacer 51 (pressing member) is provided.

As shown in FIG. 5, the spacer 51 is formed such that the thickness on the end portion side of the insulating reflective sheet 12 increases, and the thickness decreases as the end force of the insulating reflective sheet 12 increases. By providing such a wedge-shaped spacer 51 between the insulating reflection sheet 12 and the metal reflection sheet 13, both end forces in the X direction of the insulating reflection sheet 12 are pushed upward to the lower part of the LED22. Will be. As a result, it is possible to eliminate a gap between the insulating reflective sheet 12 and the lower portion of the LED 22 that generates leakage light. As a result, the light utilization efficiency is further improved, and a backlight device with higher luminance can be realized.

[0045] As the material of the spacer 51, for example, PET (polyester), silicon, rubber or the like can be used. In addition, the spacer 51 may be bonded to the end of the insulating reflective sheet 12, or may be bonded to the end of the metal reflective sheet 13. [Embodiment 4]

An embodiment of a liquid crystal display device provided with the illumination device according to the present invention will be described. In addition, about the structure similar to the structure demonstrated in each above-mentioned embodiment, the same referential mark as those embodiment is attached, and detailed description is abbreviate | omitted.

FIG. 6 is a cross-sectional view showing a schematic configuration of the liquid crystal display device 60 according to the present embodiment. As shown in FIG. 6, the liquid crystal display device 60 has a configuration in which a backlight device 10 is provided on the back surface of the liquid crystal display element 70. On the upper layer of the light guide 11 of the knocklight device 10, a diffusion sheet 74, a prism sheet 75, and the like are laminated. Although not shown in FIG. 6, various optical sheets may be laminated on the display surface of the liquid crystal display element 70. Further, the illustration of the housing for holding the liquid crystal display element 70 and the backlight device 10 together is also omitted in FIG.

The liquid crystal display element 70 has a configuration in which a liquid crystal 73 is filled between a pair of glass substrates 71 and 72 bonded together via a sealing material (not shown). The liquid crystal display element that can be combined with the lighting device of the present invention may be a transmissive type or a transflective type, and its element configuration, drive mode, and the like are arbitrary. However, as an example, the glass substrate 71 is an active matrix substrate including, for example, a TFT (Thin Film Transistor), and the glass substrate 72 is, for example, an opposing substrate including a counter electrode.

[0049] As described above, the liquid crystal display device 60 according to the present embodiment includes the knocklight device 10 with high light use efficiency and high brightness, and thus has excellent display quality and low power consumption. It has the effect that it can be done. In the present embodiment, the liquid crystal display device including the backlight device 10 according to the first embodiment is illustrated, but the liquid crystal using the above-described knock light device 30, 40, or 50 instead of the backlight device 10. The display device has the same effect.

As described above, the embodiments of the illumination device (backlight device) and the liquid crystal display device using the same according to the present invention have been described. However, the present invention is not limited to these specific embodiments. Absent.

[0051] For example, in the above-described embodiment, the backlight device including the flat light guide is illustrated, but the shape of the light guide is not limited to the flat shape, and may be a wedge shape, for example. . Also, Arbitrary patterns may be formed on the bottom and surface of the light guide.

[0052] In the above-described embodiment, a force LED unit exemplifying a configuration in which a pair of LED units are provided on both sides of the light guide may be provided only on the side surface. Alternatively, the LED unit may be installed on one side and the side adjacent to the side (that is, in an L shape).

[0053] Furthermore, in the above-described embodiment, the number of LEDs as the force light source exemplifying a configuration using an LED unit in which a plurality of LEDs are arranged is arbitrary.

Industrial applicability

The present invention is industrially applicable as a lighting device with high light utilization efficiency and high brightness, and a high-quality liquid crystal display device using the same.

Claims

The scope of the claims

[1] It comprises a light guide and a light emitting element disposed opposite to the side surface of the light guide, and propagates light incident on the side surface from the light emitting element inside the light guide. In the illuminating device that emits planar light of one principal surface force of the light guide,

An insulating reflecting member installed outside a main surface opposite to one main surface of the light guide; and a metal reflecting member laminated on the opposite side of the light guide in the insulating reflecting member. A lighting device characterized by the above.

[2] The light emitting element has a wiring terminal at a position facing a side surface of the light guide, and the metal reflecting member has conductivity.

The lighting device according to claim 1, wherein a length of the metal reflecting member in a normal direction of a side surface facing the light emitting element in the light guide is shorter than a length of the insulating reflecting member.

[3] The lighting device according to claim 2, wherein an insulating member is provided between an end of the metal reflecting member and the wiring terminal.

[4] The light emitting element has a wiring terminal at a position facing a side surface of the light guide, and the metal reflecting member has conductivity.

2. The lighting device according to claim 1, wherein an end portion of the insulating reflecting member is interposed between an end portion of the metal reflecting member and the wiring terminal.

[5] The end of the insulating reflecting member emits the light between the end of the insulating reflecting member and the metal reflecting member in the normal direction of the side surface facing the light emitting element in the light guide. 3. The illumination device according to claim 1, further comprising a pressing member that presses toward the element side.

[6] A liquid crystal display device comprising the illumination device according to any one of claims 1 to 5 and a liquid crystal display element.